W3C home > Mailing lists > Public > www-validator@w3.org > October 2002

Re: Beta: XHTML 1.0 in XML Schema

From: Terje Bless <link@pobox.com>
Date: Mon, 28 Oct 2002 07:01:50 +0100
To: W3C Validator <www-validator@w3.org>
cc: Masayasu Ishikawa <mimasa@w3.org>
Message-ID: <a01060005-1021-C0A69E4AEA3A11D6920A00039300CF5C@[]>

Bjoern Hoehrmann <derhoermi@gmx.net> wrote:

>(located at <http://www.bjoernsworld.de/temp/xhtml1-schema.html>) should
>vaidate as valid according to the associated document type definition (I
>am not sure whether to call it a valid XHTML 1.0 Strict document due to
>the informative nature of the http://www.w3.org/TR/xhtml1-schema/ note).

That Note, BTW, uses the term "DOCTYPE declaration". :-)

>The validator says it's invalid XHTML 1.0 Strict, see

Yes, because the Validator is obeying the, uhm, Document Type Declaration
you gave it. SGML does not define (AFAICT, that is) the behaviour of
processors when the FPI and the SI refer to different External Subsets.

In particular (still AFAICT), even though a precedence is not established
between the FPI and the SI, processors are allowed to prefer the FPI for
looking up the External Subset in it's own Catalog instead of resolving the
SI. Since the latter is left to implementors, it's precise semantics are in
practice undefined (cf. the recent desire to use URIs as Names)!

In any case, in the Validator's specific case, allowing the SI to take
precedence is not an option. It would require substantial changes to our
XML Parser and/or introducing a caching proxy between it and the world
(adding another layer of complexity and potential source of problems) to
avoid overloading both itself and the www.w3.org servers.

>the same document with modified attribute declarations in the internal
>subset [...] *does* validate as XHTML 1.0 Strict [...]

As the XHTML 1.0 Schema Note also makes perfectly clear! To use both "DTD"
and Schema in the same document, the Document Type Declaration needs to be
extended compared to XHTML 1.0, and goes on to suggest you add the
necessary magic pixie dust in the Internal Subset.

>That's unsatisfactory.


Mimasa? You still on this list? What are the chances there will be a
release of "-//W3C//DTD XHTML 1.0 Strict + Schema//EN"?

It is, IMO, extremely unfortunate that one not take advantage of the
opportunity to let DTDs and Schema coexist when doing so requires so little
effort. And using the same FPI for two substantially different "DTDs" falls
under the heading of a "bug" IMO.

[ No CC sent to www-html-editor@w3.org; I suggest anyone that ]
[ wants to "Raise The Issue" do so in direct email and not as ]
[ a CCs of a mailinglist message. :-)                         ]

We've gotten to a point where a human-readable,  human-editable text format
forstructured data has become a complex nightmare where somebody can safely
say "As many threads on xml-dev have shown, text-based processing of XML is
hazardous at best" and be perfectly valid in saying it.     -- Tom Bradford
Received on Monday, 28 October 2002 01:01:55 UTC

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